mention runtime.exs

docs/source/concepts.rst

@@ -69,7 +69,9 @@ By default, the buildpacks we use include
   - https://github.com/gigalixir/gigalixir-buildpack-releases
 
     - To run mix release if you are running Elixir 1.9 and using the built-in releases
-    - This is only run if you have a config/releases.exs file present.
+    - This is only run if you have a config/releases.exs file present. 
+
+      .. Note:: Elixir 1.11 adds :bash:`config/runtime.exs`. If you use that instead, then you'll want to specify buildpacks since we can no longer detect if you want releases or mix mode. See :ref:`buildpacks-releases`.
 
   - https://github.com/gigalixir/gigalixir-buildpack-mix.git
 

docs/source/config.rst

@@ -30,6 +30,8 @@ For elixir releases, always use :elixir:`System.get_env("FOO")`, but put it in y
 
 For example with distillery, to introduce a new :bash:`MY_CONFIG` env var is add something like this to your :bash:`prod.exs` file
 
+.. Note:: Elixir 1.11 adds :bash:`config/runtime.exs`. If you use that instead, then you'll want to specify buildpacks since we can no longer detect if you want releases or mix mode. See :ref:`buildpacks-releases`.
+
 .. code-block:: elixir
 
     config :myapp,

docs/source/modify-app/index.rst

@@ -33,7 +33,7 @@ If you choose Elixir releases, see :ref:`modifying existing app with Elixir rele
 
 If you choose distillery, see :ref:`modifying existing app with distillery`.
 
-* We say easy configuration here because some customers get confused about the difference between prod.exs and releases.exs. Distillery can be even more confusing with its :bash:`REPLACE_OS_VARS` syntax.
+* We say easy configuration here because some customers often get confused about the difference between prod.exs, releases.exs, and runtime.exs. Distillery can be even more confusing with its :bash:`REPLACE_OS_VARS` syntax.
 
 .. toctree::
     :hidden:

docs/source/modify-app/releases.rst

@@ -8,6 +8,8 @@ Configuration and Secrets
 
 Gigalixir auto-detects that you want to use Elixir Releases if you have a :bash:`config/releases.exs` file, so let's create one.
 
+.. Note:: Elixir 1.11 adds :bash:`config/runtime.exs`. If you use that instead, then you'll want to specify buildpacks since we can no longer detect if you want releases or mix mode. See :ref:`buildpacks-releases`.
+
 .. code-block:: bash
 
     echo "import Config" > config/releases.exs
@@ -89,6 +91,8 @@ If everything works, commit the changes
 
 Continue to :ref:`set up deploys`.
 
+.. _`buildpack-releases`:
+
 Specify Buildpacks (optional)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^